Structural color pixels, such as diffraction gratings, sub-wavelength structures, and plasmonic structures, display colors owing to interaction of light with physical structures. The structural colors display unique optical effects and have been widely used in security applications. Color images comprising diffractive grating structures have been used in authentication and anti-counterfeit applications, such as those demonstrated by Lai et al. (U.S. Pat. No. 7,113,690 B2, Sep. 26, 2006) and Schnieper et al. (U.S. Pat. No. 7,787,182 B2, Aug. 31, 2010; U.S. Pat. No. 8,270,050 B2, Sep. 18, 2012). A metal film having sub-wavelength apertures can be patterned to display color images which can be applied towards security applications, in accordance with the teaching of Kaminska et al. (U.S. Pat. No. 8,253,536 B2. Aug. 28, 2012), having a common co-inventor as the present application. Full color optical displays comprising nanostructure arrays with RGB or CMYK colors have been demonstrated by Landrock et al. (PCT Patent Publication No. WO 2014/179891 A1, Nov. 13, 2014; PCT Patent Publication No. WO 2014/179892 A1, Nov. 13, 2014). Kumar et al. (Nat. Nanotechnol. 7, 557, 2012) teaches that sub-wavelength structures comprising apertures and disks can serve as bright color pixels that allow for printing a color image in a resolution comparable with optical diffraction limit.
Conventional techniques of manufacturing structural color image display devices usually include originating a master stamp using micro/nano fabrication tools according to the desired image and replicating the devices into large quantity using a roll-to-roll process. Chuo et al. (Nanotechnol. 24, 055304, 2013) teaches that one image master stamp comprised of nano-hole arrays can be originated using electron beam lithography (EBL) followed by reactive ion etching (RIE). Laser interference lithography (LIL) is another effective method to expose micro-grating patterns and to originate an image master stamp, in accordance with the teaching of Gagnon et al. (PCT Patent Publication No. WO 2005/053115 A2, Jun. 9, 2005). Both EBL and LIL techniques expose the image patterns onto the substrate point by point and the fabrication process is usually lengthy and expensive. Zone-plate-array lithography (ZPAL) is a technique that can write the subregion of the image pattern in parallel with high throughput, in accordance with the teaching of Smith et al. (Microelectronic Engineering, 83, pp. 956-961, 2006). These above-mentioned popular manufacturing methods all require expensive equipment and it is not practical to include personalized or customized information into the color display device.
Other difficulties with existing systems and techniques may be appreciated in view of the Detailed Description of Example Embodiments herein below.